Found that this did exactly what I wanted with great results

I found that this did exactly what I wanted with great results.I was using it to repair old tatty grouting in between grey granite patio slabs.

The job was done quickly once the vacuum sealed bag was opened – a must as it starts to set when the air gets to it, so you only have 45 minutes to complete while the geo-fix is still workable. The hard work was in doing the preparation, as the gaps need to be 25mm deep x 5mm wide(minimum), but the actual application of geo-fix was easy – just brush into the gaps and compact down (I used the edge of my hand) – repeat, when compacted until the gap, is filled with packed down geo-fix and then simply slide along with a brick mortar tool or use a short piece of hose pipe to give a nice u shaped smooth finish – then stand back and admire! 4 hours later it is set hard but is still water permeable so you won’t get standing water on your patio when it rains.